The discovery happened because the amateur historian suffered a sudden loss of hearing and took leave from his job to go browse the archives in Dublin. A special Christmas supplement to the regular newspaper from 1890 and he decided to just browse it for fun ?
Well, he lived in Dublin, where Stoker lived, and I'd bet the library he visited had a special Stoker collection that might have attracted a fan. There's also the fact that Stoker's mother Charlotte helped open state schools for deaf children; so there may have been some connection there, too. But yeah, on such strange coincidences many discoveries rest.
It's interesting how much you can find just by reading old newspapers and magazines. Everybody just reads Wikipedia now, even journalists, so it's become basically the sole source of truth. If it's not in there, it's not on record. But if you scratch the surface just a little bit, you find tidbits that are only mentioned on places like ancient newsgroup threads, or sometimes not mentioned at all on the public web. Libraries, man!
The funds from publishing also going to an org focused on those who suffer hearing loss—-which is for Stoker’s mother who was a hearing loss campaigner.
Serendipitous.